I have a button on a custom object called Alerts.  When the button is clicked we basically want it to clone all information, but I want a Master Alert field filled in with the original alert's ID:

So for instance
An Initial Alert is created - Alert 110
I click the Update button on Alert 110 and it clones it (creating Alert 111 and opening an edit of the new alert) I can edit all I want and on save I want Alert 110 to be in the Master Alert field.  
So Now if I click Update on Alert 111 (creating Alert 112 and opening an edit of the new alert) I can edit all I want and on Save I want Alert 110 to be in the Master Alert field.

Here is my mess of code Class:
public class CW_alertUpdate{

public final Alerts__c alertID;
public Alerts__c newAlert{get;set;}
  
    public CW_alertUpdate(ApexPages.StandardController controller) {
        //gets fields from previous case
        alertID = [SELECT Id FROM Alerts__c WHERE Id = :ApexPages.currentPage().getParameters().get('alertID')];
        //isDisplayPopUp = true;
        //gets fields from pop-up
        //this.formFields = (Case)Controller.getRecord();
     }
     public pageReference autorun(){
         //create a new Case
         Alerts__c newAlert = new Alerts__c();
         
          // Fill in the values for the new record from previous case
       
         newAlert.Master_Alert_Lookup__c = alertID.Id;
        
        //Insert the new Case record
        insert newAlert;
        system.debug(newAlert);
        PageReference retPage = new PageReference('/' + newAlert.id);
        return retPage;
       }
    }

Functionally it works, BUT it creates one Alert with all the previous alert's info and then creates a 2nd Alert with just the updated Master Alert field.  How do I make it work and just create 1 Alert?



Update button:
/a0H/e?retURL={!Alerts__c.Id}&00Ne0000000jigO={!Alerts__c.Incident_Start__c}&00Ne0000000jifu={!Alerts__c.Product__c}&00Ne0000000jigd={!Alerts__c.Team_List__c}&CF00Ne0000000jigi={!Alerts__c.Incident_Manager__c}&CF00Ne0000000jigi_lkid={!Alerts__c.Incident_ManagerId__c}&00Ne0000000jigT={!Alerts__c.Incident_Reported__c}&00Ne0000000jifk={!Alerts__c.Subject__c}&CF00Ne0000000jigs={!Alerts__c.Account_Name__c}&CF00Ne0000000jigs_lkid={!Alerts__c.Account_NameId__c}&
00Ne0000000jifz={!Alerts__c.Customer_Impact__c}&00Ne0000000jig4={!Alerts__c.Completed_Actions__c}&00Ne0000000jig9={!Alerts__c.Next_Actions__c}&CF00Ne0000000jigE={!Alerts__c.Incident_Ticket_Number__c}&CF00Ne0000000jigE_lkid={!Alerts__c.Incident_Ticket_NumberId__c}&00Ne0000000dZZQ={!Alerts__c.CGM_P1_AMERICAS_MANNED__c}&00Ne0000000dZZL={!Alerts__c.CGM_P1_APD_MANNED__c}&00Ne0000000dZZH={!Alerts__c.CGM_P1_Command__c}&00Ne0000000dZZG={!Alerts__c.CGM_P1_EAME_MANNED__c}&saveURL=/apex/CW_AlertUpdate?alertID={!Alerts__c.Id}